Connecting two 6500's together

I have to connect two 6500's together for an odd reason. 6509-A does not have connectivity to the internet and 6509-B does.

6509-A ====== 6509-B ======= Internet

Now, Can i connect two 6500's together via gbic ports and not assign vlan's on any of those ports and expect them to communicate fine? I just want them to be communicating on layer3 and hence would have to configure an IP address on each of the 6509's

Where would I configure these IP addresses?

I dont' want to use trunking, etc
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lrmooreConnect With a Mentor Commented:
So, we're back to the same common VLAN between the two switches. Create VLAN 83 on both, assign the appropriate switch port to VLAN 83,  connect them together, and create the vlan interface with the appropriate IP addressing, enable routing, set the default gateway and off you go..
You have to use trunking, otherwise you will only be able to send one vlan's packets over the link.
You have more than one vlan on each switch right? If you dont trunk the uplinks, you have to use an uplink per vlan.

Why not set it up like this

   ||     \
   ||      router------Internet
   ||    /

That way you have redundancy built into your switched network
NicBrey is correct.
Unless the 6059s have MSFC L3 capabilities, you have to trunk the vlans.
You assign the management IP address to the switch SC0 interface which has absolutely nothing to do with routing packets from any vlans..
If you've made the investment in this much hardware, take the time to learn about the capabilities and put them to best use, or hire a consultant to come in and help you get them set up right.
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Sorry, Bill. Had a rough day and took it out on you... please accept my sincerest apologies...


How about editing my comments, and we take up the issue again?

Even if you have no need for VLAN’s, and regardless of whether you 6509’s have L3 capabilities, you should trunk between them. The fact is, needs frequently change, and you could very easily find your self in the future with a network under heavy use, wishing very much you had configured trunks between the switches. And since there are no drawbacks to having trunks, even if you don’t need them, you might at well start off with them in the first place.

As for the 6509 that won’t connect to the Internet, if you can ping the other 6509 it probably is because the default route is not set. For the cat OS the command would be “set ip route x.x.x.x” and for ISO in the config mode you’d enter this line “ x.x.x.x” the x.x.x.x is where you put the IP addres of your default gateway. For setting the IP address for cat OS it’s “set interface sc0 1 ip-address/subnet-mask” and for IOS in the config mode “interface VLAN1” then enter “ p address”.

billwhartonAuthor Commented:
Oks, here goes:

Supposing you only had 6509-A ====== 6509-B, and you had an end-to-end vlan on this infrastructure, then you would configure trunking because you want vlan 3 on A to be in the same broadcast domain as vlan 3 on B.

However, if you had 6509-A ====== 6509-B ======= Internet, and A & B didn't share broadcast domains or VLAN's and you simply needed route layer 3 data, then why would you feel the necessity of a trunk between A & B.

If vlan's on 6509-A want to access the Internet, they don't need to be switched on to B but they simply need to be routed to B. A default gateway setting on 6509-A would satisfy this requirement and hence I am interested in simply setting up an access port between A & B and not a trunk.

I cannot do any changes of design, etc. This is a very fixed nature environment and I only have to establish communication with B because for Internet connectivity.

lrmoore, you weren't harsh on me if you felt that way. Further more, i have worked with the 6509's myself but I tend to oversimplify questions in here at the start and then complicate them further as threads kept getting added on.
The bottom line is that you need a common vlan where both sides can touch the internet router.
Where is the L3 routing between VLAN's being handled?

Do you have MSFC's on the 6509s??

Yes ---> which vlan is default vlan connected to Internet gateway?
That VLAN needs to be common on both switches. No other vlans need to see each other.
The only way for a vlan to be common to both switches is to setup VTP trunking, or use the default vlan 1.

Internet router plugged into vlan 1
6509A  port 4/48 = vlan 1
6509B  port 6/48 = vlan 1
Plug these two ports together with a x-over cable
Now, assuming you have MSFC to route vlan3 'through' vlan 1 to the router, you're in good shape.
billwhartonAuthor Commented:
MSFC's are on both A & B.

The point of interconnectivity on both switches in gigabit fiber port 3/1 and this port has been configured as an access port as follows:
On A, 3/1 is on vlan83 and the IP address on the MSFC for vlan83 is
On B, 3/1 is on vlan83 and the IP address on the MSFC for vlan83 is
OK, that makes sense. Can you ping one from the other?
If you can ping from A,, then you should just be able to point your default gateway for A to that IP

    ip route

Your problem will be that you will be working from other vlan's / subnets, and you now need to enable some type of dynamic routing between the MSFC's... Do you have anything setup now?
billwhartonAuthor Commented:
Well, I don't have the 6509's with me to try that out; actually installing this tomorrow.

My question was: Can one simply configure access ports in this fashion and expect them to work correctly?
That's a sort of 'it depends'.
Are you running the switches in pure IOS mode, or mixed IOS/CatOS mode?
If pure IOS mode, then sure, no problem.
If mixed mode, then you have to at least make sure that the switchports are set for VLAN83 at the same time.
billwhartonAuthor Commented:

My original plan was to use 'no switchport' which you seem to be indicating. But this plan had to be thrown out when I realized I am running hubrid.
billwhartonAuthor Commented:
and if it doesn't, I am getting ready for Plan B which would be convert the 6509 to native IOS mode.
Sounds like a plan. Gotta run for the evening, I'll check back later.
Good luck!
couldn't you create a layer3 transit lan between the 6509's?

that way, you wouldn't have to create a l2 trunk between the devices.

switchA could have:

vlan 2 with all the hosts
vlan 3 as the 'transit' lan between the switches. /29 or similar small LAN

one switchport would be in vlan 3. on switch A.

On switch B, you'll also have a Vlan 3 interface and the one switchport connecting to the vlan 3 switchport on 6509-A.

Switch B can also have other vlans that are routed and local to that switch as well.

Switch 6509A can either have a default route pointing to switch B's vlan3 interface and switch 6509-B point to the internet connection, or you could enable some dynamic routing protocol (eigrp, ospf, isis, etc...) and have the default route on switch 6509-B redistributed to switch A.

That way you wouldn't have to have any sort of trunking between the switches.

So, in this scenario, each 6509 would have a minimum of two layer 3 vlans.

If you need config examples, myself or any of the other respondants surely could provide you with what you need.

Even though it can work without trunking, the reason I highly recommend starting off with trunking is things change, and although today you don’t need them, all to often the need to share a VLAN from one switch to another arises. Then you end up knocking down the network and disrupting traffic to configure trunks between the switches. I have had to do this on several networks already, and if they had started off with trunking in the first place it never would have happened. And since there are no drawbacks from using trunks to connect switches together, especially since you can prune any VLAN’s you don’t want running across the trunk, you might as well start off with them in the first place. That way latter, if you need them, they are in place, and if you don’t, no harm has been done.    
Any luck with this, Bill?
billwhartonAuthor Commented:
worked like a charm.

I'm kind of tired awarding you points all the time

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